qemu/hw/i8259.c
bellard ba91cd80d5 fixed very unlikely irq bug
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@749 c046a42c-6fe2-441c-8c8c-71466251a162
2004-04-25 18:03:53 +00:00

431 lines
11 KiB
C

/*
* QEMU 8259 interrupt controller emulation
*
* Copyright (c) 2003-2004 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "vl.h"
/* debug PIC */
//#define DEBUG_PIC
//#define DEBUG_IRQ_LATENCY
typedef struct PicState {
uint8_t last_irr; /* edge detection */
uint8_t irr; /* interrupt request register */
uint8_t imr; /* interrupt mask register */
uint8_t isr; /* interrupt service register */
uint8_t priority_add; /* highest irq priority */
uint8_t irq_base;
uint8_t read_reg_select;
uint8_t poll;
uint8_t special_mask;
uint8_t init_state;
uint8_t auto_eoi;
uint8_t rotate_on_auto_eoi;
uint8_t special_fully_nested_mode;
uint8_t init4; /* true if 4 byte init */
} PicState;
/* 0 is master pic, 1 is slave pic */
static PicState pics[2];
static int pic_irq_requested;
/* set irq level. If an edge is detected, then the IRR is set to 1 */
static inline void pic_set_irq1(PicState *s, int irq, int level)
{
int mask;
mask = 1 << irq;
if (level) {
if ((s->last_irr & mask) == 0)
s->irr |= mask;
s->last_irr |= mask;
} else {
s->last_irr &= ~mask;
}
}
/* return the highest priority found in mask (highest = smallest
number). Return 8 if no irq */
static inline int get_priority(PicState *s, int mask)
{
int priority;
if (mask == 0)
return 8;
priority = 0;
while ((mask & (1 << ((priority + s->priority_add) & 7))) == 0)
priority++;
return priority;
}
/* return the pic wanted interrupt. return -1 if none */
static int pic_get_irq(PicState *s)
{
int mask, cur_priority, priority;
mask = s->irr & ~s->imr;
priority = get_priority(s, mask);
if (priority == 8)
return -1;
/* compute current priority. If special fully nested mode on the
master, the IRQ coming from the slave is not taken into account
for the priority computation. */
mask = s->isr;
if (s->special_fully_nested_mode && s == &pics[0])
mask &= ~(1 << 2);
cur_priority = get_priority(s, mask);
if (priority < cur_priority) {
/* higher priority found: an irq should be generated */
return (priority + s->priority_add) & 7;
} else {
return -1;
}
}
/* raise irq to CPU if necessary. must be called every time the active
irq may change */
static void pic_update_irq(void)
{
int irq2, irq;
/* first look at slave pic */
irq2 = pic_get_irq(&pics[1]);
if (irq2 >= 0) {
/* if irq request by slave pic, signal master PIC */
pic_set_irq1(&pics[0], 2, 1);
pic_set_irq1(&pics[0], 2, 0);
}
/* look at requested irq */
irq = pic_get_irq(&pics[0]);
if (irq >= 0) {
if (irq == 2) {
/* from slave pic */
pic_irq_requested = 8 + irq2;
} else {
/* from master pic */
pic_irq_requested = irq;
}
#if defined(DEBUG_PIC)
{
int i;
for(i = 0; i < 2; i++) {
printf("pic%d: imr=%x irr=%x padd=%d\n",
i, pics[i].imr, pics[i].irr, pics[i].priority_add);
}
}
printf("pic: cpu_interrupt req=%d\n", pic_irq_requested);
#endif
cpu_interrupt(cpu_single_env, CPU_INTERRUPT_HARD);
}
}
#ifdef DEBUG_IRQ_LATENCY
int64_t irq_time[16];
#endif
#if defined(DEBUG_PIC)
int irq_level[16];
#endif
void pic_set_irq(int irq, int level)
{
#if defined(DEBUG_PIC)
if (level != irq_level[irq]) {
printf("pic_set_irq: irq=%d level=%d\n", irq, level);
irq_level[irq] = level;
}
#endif
#ifdef DEBUG_IRQ_LATENCY
if (level) {
irq_time[irq] = cpu_get_ticks();
}
#endif
pic_set_irq1(&pics[irq >> 3], irq & 7, level);
pic_update_irq();
}
/* acknowledge interrupt 'irq' */
static inline void pic_intack(PicState *s, int irq)
{
if (s->auto_eoi) {
if (s->rotate_on_auto_eoi)
s->priority_add = (irq + 1) & 7;
} else {
s->isr |= (1 << irq);
}
s->irr &= ~(1 << irq);
}
int cpu_get_pic_interrupt(CPUState *env)
{
int irq, irq2, intno;
/* signal the pic that the irq was acked by the CPU */
irq = pic_irq_requested;
#ifdef DEBUG_IRQ_LATENCY
printf("IRQ%d latency=%0.3fus\n",
irq,
(double)(cpu_get_ticks() - irq_time[irq]) * 1000000.0 / ticks_per_sec);
#endif
#if defined(DEBUG_PIC)
printf("pic_interrupt: irq=%d\n", irq);
#endif
if (irq >= 8) {
irq2 = irq & 7;
pic_intack(&pics[1], irq2);
irq = 2;
intno = pics[1].irq_base + irq2;
} else {
intno = pics[0].irq_base + irq;
}
pic_intack(&pics[0], irq);
pic_update_irq();
return intno;
}
static void pic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
PicState *s = opaque;
int priority, cmd, irq;
#ifdef DEBUG_PIC
printf("pic_write: addr=0x%02x val=0x%02x\n", addr, val);
#endif
addr &= 1;
if (addr == 0) {
if (val & 0x10) {
/* init */
memset(s, 0, sizeof(PicState));
s->init_state = 1;
s->init4 = val & 1;
if (val & 0x02)
hw_error("single mode not supported");
if (val & 0x08)
hw_error("level sensitive irq not supported");
} else if (val & 0x08) {
if (val & 0x04)
s->poll = 1;
if (val & 0x02)
s->read_reg_select = val & 1;
if (val & 0x40)
s->special_mask = (val >> 5) & 1;
} else {
cmd = val >> 5;
switch(cmd) {
case 0:
case 4:
s->rotate_on_auto_eoi = cmd >> 2;
break;
case 1: /* end of interrupt */
case 5:
priority = get_priority(s, s->isr);
if (priority != 8) {
irq = (priority + s->priority_add) & 7;
s->isr &= ~(1 << irq);
if (cmd == 5)
s->priority_add = (irq + 1) & 7;
pic_update_irq();
}
break;
case 3:
irq = val & 7;
s->isr &= ~(1 << irq);
pic_update_irq();
break;
case 6:
s->priority_add = (val + 1) & 7;
pic_update_irq();
break;
case 7:
irq = val & 7;
s->isr &= ~(1 << irq);
s->priority_add = (irq + 1) & 7;
pic_update_irq();
break;
default:
/* no operation */
break;
}
}
} else {
switch(s->init_state) {
case 0:
/* normal mode */
s->imr = val;
pic_update_irq();
break;
case 1:
s->irq_base = val & 0xf8;
s->init_state = 2;
break;
case 2:
if (s->init4) {
s->init_state = 3;
} else {
s->init_state = 0;
}
break;
case 3:
s->special_fully_nested_mode = (val >> 4) & 1;
s->auto_eoi = (val >> 1) & 1;
s->init_state = 0;
break;
}
}
}
static uint32_t pic_poll_read (PicState *s, uint32_t addr1)
{
int ret;
ret = pic_get_irq(s);
if (ret >= 0) {
if (addr1 >> 7) {
pics[0].isr &= ~(1 << 2);
pics[0].irr &= ~(1 << 2);
}
s->irr &= ~(1 << ret);
s->isr &= ~(1 << ret);
if (addr1 >> 7 || ret != 2)
pic_update_irq();
} else {
ret = 0x07;
pic_update_irq();
}
return ret;
}
static uint32_t pic_ioport_read(void *opaque, uint32_t addr1)
{
PicState *s = opaque;
unsigned int addr;
int ret;
addr = addr1;
addr &= 1;
if (s->poll) {
ret = pic_poll_read(s, addr1);
s->poll = 0;
} else {
if (addr == 0) {
if (s->read_reg_select)
ret = s->isr;
else
ret = s->irr;
} else {
ret = s->imr;
}
}
#ifdef DEBUG_PIC
printf("pic_read: addr=0x%02x val=0x%02x\n", addr1, ret);
#endif
return ret;
}
/* memory mapped interrupt status */
uint32_t pic_intack_read(CPUState *env)
{
int ret;
ret = pic_poll_read(&pics[0], 0x00);
if (ret == 2)
ret = pic_poll_read(&pics[1], 0x80) + 8;
/* Prepare for ISR read */
pics[0].read_reg_select = 1;
return ret;
}
static void pic_save(QEMUFile *f, void *opaque)
{
PicState *s = opaque;
qemu_put_8s(f, &s->last_irr);
qemu_put_8s(f, &s->irr);
qemu_put_8s(f, &s->imr);
qemu_put_8s(f, &s->isr);
qemu_put_8s(f, &s->priority_add);
qemu_put_8s(f, &s->irq_base);
qemu_put_8s(f, &s->read_reg_select);
qemu_put_8s(f, &s->poll);
qemu_put_8s(f, &s->special_mask);
qemu_put_8s(f, &s->init_state);
qemu_put_8s(f, &s->auto_eoi);
qemu_put_8s(f, &s->rotate_on_auto_eoi);
qemu_put_8s(f, &s->special_fully_nested_mode);
qemu_put_8s(f, &s->init4);
}
static int pic_load(QEMUFile *f, void *opaque, int version_id)
{
PicState *s = opaque;
if (version_id != 1)
return -EINVAL;
qemu_get_8s(f, &s->last_irr);
qemu_get_8s(f, &s->irr);
qemu_get_8s(f, &s->imr);
qemu_get_8s(f, &s->isr);
qemu_get_8s(f, &s->priority_add);
qemu_get_8s(f, &s->irq_base);
qemu_get_8s(f, &s->read_reg_select);
qemu_get_8s(f, &s->poll);
qemu_get_8s(f, &s->special_mask);
qemu_get_8s(f, &s->init_state);
qemu_get_8s(f, &s->auto_eoi);
qemu_get_8s(f, &s->rotate_on_auto_eoi);
qemu_get_8s(f, &s->special_fully_nested_mode);
qemu_get_8s(f, &s->init4);
return 0;
}
/* XXX: add generic master/slave system */
static void pic_init1(int io_addr, PicState *s)
{
register_ioport_write(io_addr, 2, 1, pic_ioport_write, s);
register_ioport_read(io_addr, 2, 1, pic_ioport_read, s);
register_savevm("i8259", io_addr, 1, pic_save, pic_load, s);
}
void pic_info(void)
{
int i;
PicState *s;
for(i=0;i<2;i++) {
s = &pics[i];
term_printf("pic%d: irr=%02x imr=%02x isr=%02x hprio=%d irq_base=%02x rr_sel=%d\n",
i, s->irr, s->imr, s->isr, s->priority_add, s->irq_base, s->read_reg_select);
}
}
void pic_init(void)
{
pic_init1(0x20, &pics[0]);
pic_init1(0xa0, &pics[1]);
}